Why? The natural “up” direction is north, and east goes great with it like that’s where the sun comes up and also arrows pointing to N and E look like the coordinate axes in a default oriented graph.
Because some people hundreds and thousands of years ago drew it like that on maps, and people kept doing it that way for cross-compatibility reasons, and now it's a convention.
And the best part is that it depends on culture. In ancient Hebrew, east was venerated for a variety of reasons and was given the distinction as "up" (although I'm not sure that distinction really maps to our concept of up).
I would imagine so, yes. Hence the cultural implications of "beginning" or "origin" since the sun was no doubt viewed as the locus of life.
One of the interesting implications is how they view the past as east and the future as west (or conversely, the past as in front of you and the future as behind you). I'm not precisely sure I yet understand why this is, but I wonder if it's a matter of visibility? e.g., we can "see" the past but not the future.
